As a solid-state imaging device, for example, a charge coupled device (CCD) image sensor (CCD type solid-state imaging device) and a complementary metal oxide semiconductor (CMOS) image sensor (CMOS type solid-state imaging device) have been known. The solid-state imaging device accumulates electric charges according to an amount of incident light and performs photoelectric conversion for outputting an electric signal corresponding to the accumulated electric charges. However, since there is an upper limit level in an electric charge accumulating amount, if light of which an amount is equal to or more than the upper limit level is received in a certain exposure time, the accumulated electric charge amount reaches a saturation level. As a result, a tone equal to or higher than the saturation level cannot be expressed, and so-called halation occurs.
The halation can be avoided by releasing a shutter in a short time so that the accumulated electric charge mount is not saturated. However, in a case where a scene with a high dynamic range (HDR) in which a bright region and a dark region are mixed is imaged, the electric charges cannot be sufficiently accumulated regarding the dark region. Therefore, the dark region is in a so-called blackened state in which a SN ratio (S/N) is poor and an image quality is deteriorated.
As a technology of imaging a scene with a high dynamic range, a method of serially imaging a plurality of images with different exposure times and synthesizing the images to extend the dynamic range has been known. However, in this method, since the plurality of images imaged at imaging timings separated from each other is synthesized, there has been a problem in that multiple image is easily created if a subject moves between the imaging timings or in that a frame rate at which a synthesized image is obtained is lowered as the number of imaging images is increased.
Whereas, there is a technology for obtaining the plurality of images under a plurality of times of exposures for one imaging by imaging images as performing control so that exposure times are respectively different for pixels, instead of serially imaging the plurality of images, and synthesizing the plurality of images to generate an image with a high dynamic range (for example, Patent Documents 1 and 2). According to this technology, the scene with a high dynamic range can be imaged without saturation (no halation) and without causing blackening.